Waiting on subs, need to start making enclosure

Alright, so i settled on it. I'm not going to get anything better for the money and ended up getting two 12'' type r's. As of right now, thinking of running it with a Hifonics BXi 2008D but have yet to purchase it.

They are going in a 1989 Buick century with a fairly big trunk. I measured once before, but it is **** cold and i do not have the balls to go out and measure right now.

I know from previous measurements i can fit a 38'' x 19'' x 14'' tall box in the very back and can certainly get bigger.

So heres the question, how big should i make the box. Its going to be ported and i think i want it tuned at around 32-30hz. What do you guys think?